1 #include "threadimpl.h"
2 
3 int	_threaddebuglevel;
4 
5 static	uint		threadnproc;
6 static	uint		threadnsysproc;
7 static	Lock		threadnproclock;
8 static	Ref		threadidref;
9 static	Proc		*threadmainproc;
10 
11 static	void		addproc(Proc*);
12 static	void		delproc(Proc*);
13 static	void		addthread(_Threadlist*, _Thread*);
14 static	void		delthread(_Threadlist*, _Thread*);
15 static	void		addthreadinproc(Proc*, _Thread*);
16 static	void		delthreadinproc(Proc*, _Thread*);
17 static	void		contextswitch(Context *from, Context *to);
18 static	void		procscheduler(Proc*);
19 
20 static void
21 _threaddebug(char *fmt, ...)
22 {
23 	va_list arg;
24 	char buf[128];
25 	_Thread *t;
26 	char *p;
27 	static int fd = -1;
28 
29 return;
30 	va_start(arg, fmt);
31 	vfprint(1, fmt, arg);
32 	va_end(arg);
33 return;
34 
35 	if(fd < 0){
36 		p = strrchr(argv0, '/');
37 		if(p)
38 			p++;
39 		else
40 			p = argv0;
41 		snprint(buf, sizeof buf, "/tmp/%s.tlog", p);
42 		if((fd = create(buf, OWRITE, 0666)) < 0)
43 			fd = open("/dev/null", OWRITE);
44 	}
45 
46 	va_start(arg, fmt);
47 	vsnprint(buf, sizeof buf, fmt, arg);
48 	va_end(arg);
49 	t = proc()->thread;
50 	if(t)
51 		fprint(fd, "%d.%d: %s\n", getpid(), t->id, buf);
52 	else
53 		fprint(fd, "%d._: %s\n", getpid(), buf);
54 }
55 
56 static _Thread*
57 getthreadnow(void)
58 {
59 	return proc()->thread;
60 }
61 _Thread	*(*threadnow)(void) = getthreadnow;
62 
63 static Proc*
64 procalloc(void)
65 {
66 	Proc *p;
67 
68 	p = malloc(sizeof *p);
69 	if(p == nil)
70 		sysfatal("procalloc malloc: %r");
71 	memset(p, 0, sizeof *p);
72 	addproc(p);
73 	lock(&threadnproclock);
74 	threadnproc++;
75 	unlock(&threadnproclock);
76 	return p;
77 }
78 
79 static void
80 threadstart(uint y, uint x)
81 {
82 	_Thread *t;
83 	ulong z;
84 
85 	z = x<<16;	/* hide undefined 32-bit shift from 32-bit compilers */
86 	z <<= 16;
87 	z |= y;
88 	t = (_Thread*)z;
89 
90 //print("threadstart %p\n", v);
91 	t->startfn(t->startarg);
92 //print("threadexits %p\n", v);
93 	threadexits(nil);
94 //print("not reacehd\n");
95 }
96 
97 static _Thread*
98 threadalloc(void (*fn)(void*), void *arg, uint stack)
99 {
100 	_Thread *t;
101 	sigset_t zero;
102 	uint x, y;
103 	ulong z;
104 
105 	/* allocate the task and stack together */
106 	t = malloc(sizeof *t+stack);
107 	if(t == nil)
108 		sysfatal("threadalloc malloc: %r");
109 	memset(t, 0, sizeof *t);
110 	t->stk = (uchar*)(t+1);
111 	t->stksize = stack;
112 	t->id = incref(&threadidref);
113 	t->startfn = fn;
114 	t->startarg = arg;
115 
116 	/* do a reasonable initialization */
117 	memset(&t->context.uc, 0, sizeof t->context.uc);
118 	sigemptyset(&zero);
119 	sigprocmask(SIG_BLOCK, &zero, &t->context.uc.uc_sigmask);
120 
121 	/* must initialize with current context */
122 	if(getcontext(&t->context.uc) < 0)
123 		sysfatal("threadalloc getcontext: %r");
124 
125 	/* call makecontext to do the real work. */
126 	/* leave a few words open on both ends */
127 	t->context.uc.uc_stack.ss_sp = t->stk+8;
128 	t->context.uc.uc_stack.ss_size = t->stksize-64;
129 #ifdef __sun__		/* sigh */
130 	/* can avoid this with __MAKECONTEXT_V2_SOURCE but only on SunOS 5.9 */
131 	t->context.uc.uc_stack.ss_sp = 
132 		(char*)t->context.uc.uc_stack.ss_sp
133 		+t->context.uc.uc_stack.ss_size;
134 #endif
135 	/*
136 	 * All this magic is because you have to pass makecontext a
137 	 * function that takes some number of word-sized variables,
138 	 * and on 64-bit machines pointers are bigger than words.
139 	 */
140 	z = (ulong)t;
141 	y = z;
142 	z >>= 16;	/* hide undefined 32-bit shift from 32-bit compilers */
143 	x = z>>16;
144 	makecontext(&t->context.uc, (void(*)())threadstart, 2, y, x);
145 
146 	return t;
147 }
148 
149 _Thread*
150 _threadcreate(Proc *p, void (*fn)(void*), void *arg, uint stack)
151 {
152 	_Thread *t;
153 
154 	t = threadalloc(fn, arg, stack);
155 	t->proc = p;
156 	addthreadinproc(p, t);
157 	p->nthread++;
158 	_threadready(t);
159 	return t;
160 }
161 
162 int
163 threadcreate(void (*fn)(void*), void *arg, uint stack)
164 {
165 	_Thread *t;
166 
167 	t = _threadcreate(proc(), fn, arg, stack);
168 	return t->id;
169 }
170 
171 int
172 proccreate(void (*fn)(void*), void *arg, uint stack)
173 {
174 	int id;
175 	_Thread *t;
176 	Proc *p;
177 
178 	p = procalloc();
179 	t = _threadcreate(p, fn, arg, stack);
180 	id = t->id;	/* t might be freed after _procstart */
181 	_procstart(p, procscheduler);
182 	return id;
183 }
184 
185 void
186 _threadswitch(void)
187 {
188 	Proc *p;
189 
190 	needstack(0);
191 	p = proc();
192 //print("threadswtch %p\n", p);
193 	contextswitch(&p->thread->context, &p->schedcontext);
194 }
195 
196 void
197 _threadready(_Thread *t)
198 {
199 	Proc *p;
200 
201 	p = t->proc;
202 	lock(&p->lock);
203 	p->runrend.l = &p->lock;
204 	addthread(&p->runqueue, t);
205 //print("%d wake for job %d->%d\n", time(0), getpid(), p->osprocid);
206 	if(p != proc())
207 		_procwakeupandunlock(&p->runrend);
208 	else
209 		unlock(&p->lock);
210 }
211 
212 int
213 threadyield(void)
214 {
215 	int n;
216 	Proc *p;
217 
218 	p = proc();
219 	n = p->nswitch;
220 	_threadready(p->thread);
221 	_threadswitch();
222 	return p->nswitch - n;
223 }
224 
225 void
226 threadexits(char *msg)
227 {
228 	Proc *p;
229 
230 	p = proc();
231 	if(msg == nil)
232 		msg = "";
233 	utfecpy(p->msg, p->msg+sizeof p->msg, msg);
234 	proc()->thread->exiting = 1;
235 	_threadswitch();
236 }
237 
238 static void
239 contextswitch(Context *from, Context *to)
240 {
241 	if(swapcontext(&from->uc, &to->uc) < 0){
242 		fprint(2, "swapcontext failed: %r\n");
243 		assert(0);
244 	}
245 }
246 
247 static void
248 procscheduler(Proc *p)
249 {
250 	_Thread *t;
251 
252 	setproc(p);
253 	_threaddebug("scheduler enter");
254 //	print("s %p\n", p);
255 	lock(&p->lock);
256 	for(;;){
257 		while((t = p->runqueue.head) == nil){
258 			if(p->nthread == 0)
259 				goto Out;
260 			p->runrend.l = &p->lock;
261 			_threaddebug("scheduler sleep");
262 			_procsleep(&p->runrend);
263 			_threaddebug("scheduler wake");
264 		}
265 		delthread(&p->runqueue, t);
266 		unlock(&p->lock);
267 		p->thread = t;
268 		p->nswitch++;
269 		_threaddebug("run %d (%s)", t->id, t->name);
270 		contextswitch(&p->schedcontext, &t->context);
271 //print("back in scheduler\n");
272 		p->thread = nil;
273 		lock(&p->lock);
274 		if(t->exiting){
275 			delthreadinproc(p, t);
276 			p->nthread--;
277 //print("ntrhead %d\n", p->nthread);
278 			free(t);
279 		}
280 	}
281 
282 Out:
283 	_threaddebug("scheduler exit");
284 	delproc(p);
285 	lock(&threadnproclock);
286 	if(p->sysproc)
287 		--threadnsysproc;
288 	if(--threadnproc == threadnsysproc)
289 		threadexitsall(p->msg);
290 	unlock(&threadnproclock);
291 	unlock(&p->lock);
292 	free(p);
293 	setproc(0);
294 }
295 
296 void
297 _threadsetsysproc(void)
298 {
299 	lock(&threadnproclock);
300 	if(++threadnsysproc == threadnproc)
301 		exit(0);
302 	unlock(&threadnproclock);
303 	proc()->sysproc = 1;
304 }
305 
306 void**
307 procdata(void)
308 {
309 	return &proc()->udata;
310 }
311 
312 extern Jmp *(*_notejmpbuf)(void);
313 static Jmp*
314 threadnotejmp(void)
315 {
316 	return &proc()->sigjmp;
317 }
318 
319 /*
320  * debugging
321  */
322 void
323 threadsetname(char *fmt, ...)
324 {
325 	va_list arg;
326 	_Thread *t;
327 
328 	t = proc()->thread;
329 	va_start(arg, fmt);
330 	vsnprint(t->name, sizeof t->name, fmt, arg);
331 	va_end(arg);
332 }
333 
334 char*
335 threadgetname(void)
336 {
337 	return proc()->thread->name;
338 }
339 
340 void
341 threadsetstate(char *fmt, ...)
342 {
343 	va_list arg;
344 	_Thread *t;
345 
346 	t = proc()->thread;
347 	va_start(arg, fmt);
348 	vsnprint(t->state, sizeof t->name, fmt, arg);
349 	va_end(arg);
350 }
351 
352 void
353 needstack(int n)
354 {
355 	_Thread *t;
356 
357 	t = proc()->thread;
358 
359 	if((char*)&t <= (char*)t->stk
360 	|| (char*)&t - (char*)t->stk < 256+n){
361 		fprint(2, "thread stack overflow: &t=%p tstk=%p n=%d\n", &t, t->stk, 256+n);
362 		abort();
363 	}
364 }
365 
366 /*
367  * locking
368  */
369 static int
370 threadqlock(QLock *l, int block, ulong pc)
371 {
372 //print("threadqlock %p\n", l);
373 	lock(&l->l);
374 	if(l->owner == nil){
375 		l->owner = (*threadnow)();
376 //print("qlock %p @%#x by %p\n", l, pc, l->owner);
377 		unlock(&l->l);
378 		return 1;
379 	}
380 	if(!block){
381 		unlock(&l->l);
382 		return 0;
383 	}
384 //print("qsleep %p @%#x by %p\n", l, pc, (*threadnow)());
385 	addthread(&l->waiting, (*threadnow)());
386 	unlock(&l->l);
387 
388 	_threadswitch();
389 
390 	if(l->owner != (*threadnow)()){
391 		fprint(2, "%s: qlock pc=0x%lux owner=%p self=%p oops\n",
392 			argv0, pc, l->owner, (*threadnow)());
393 		abort();
394 	}
395 //print("qlock wakeup %p @%#x by %p\n", l, pc, (*threadnow)());
396 	return 1;
397 }
398 
399 static void
400 threadqunlock(QLock *l, ulong pc)
401 {
402 	lock(&l->l);
403 //print("qlock unlock %p @%#x by %p (owner %p)\n", l, pc, (*threadnow)(), l->owner);
404 	if(l->owner == 0){
405 		fprint(2, "%s: qunlock pc=0x%lux owner=%p self=%p oops\n",
406 			argv0, pc, l->owner, (*threadnow)());
407 		abort();
408 	}
409 	if((l->owner = l->waiting.head) != nil){
410 		delthread(&l->waiting, l->owner);
411 		_threadready(l->owner);
412 	}
413 	unlock(&l->l);
414 }
415 
416 static int
417 threadrlock(RWLock *l, int block, ulong pc)
418 {
419 	USED(pc);
420 
421 	lock(&l->l);
422 	if(l->writer == nil && l->wwaiting.head == nil){
423 		l->readers++;
424 		unlock(&l->l);
425 		return 1;
426 	}
427 	if(!block){
428 		unlock(&l->l);
429 		return 0;
430 	}
431 	addthread(&l->rwaiting, (*threadnow)());
432 	unlock(&l->l);
433 	_threadswitch();
434 	return 1;	
435 }
436 
437 static int
438 threadwlock(RWLock *l, int block, ulong pc)
439 {
440 	USED(pc);
441 
442 	lock(&l->l);
443 	if(l->writer == nil && l->readers == 0){
444 		l->writer = (*threadnow)();
445 		unlock(&l->l);
446 		return 1;
447 	}
448 	if(!block){
449 		unlock(&l->l);
450 		return 0;
451 	}
452 	addthread(&l->wwaiting, (*threadnow)());
453 	unlock(&l->l);
454 	_threadswitch();
455 	return 1;
456 }
457 
458 static void
459 threadrunlock(RWLock *l, ulong pc)
460 {
461 	_Thread *t;
462 
463 	USED(pc);
464 	lock(&l->l);
465 	--l->readers;
466 	if(l->readers == 0 && (t = l->wwaiting.head) != nil){
467 		delthread(&l->wwaiting, t);
468 		l->writer = t;
469 		_threadready(t);
470 	}
471 	unlock(&l->l);
472 }
473 
474 static void
475 threadwunlock(RWLock *l, ulong pc)
476 {
477 	_Thread *t;
478 
479 	USED(pc);
480 	lock(&l->l);
481 	l->writer = nil;
482 	assert(l->readers == 0);
483 	while((t = l->rwaiting.head) != nil){
484 		delthread(&l->rwaiting, t);
485 		l->readers++;
486 		_threadready(t);
487 	}
488 	if(l->readers == 0 && (t = l->wwaiting.head) != nil){
489 		delthread(&l->wwaiting, t);
490 		l->writer = t;
491 		_threadready(t);
492 	}
493 	unlock(&l->l);
494 }
495 
496 /*
497  * sleep and wakeup
498  */
499 static void
500 threadrsleep(Rendez *r, ulong pc)
501 {
502 	addthread(&r->waiting, proc()->thread);
503 	qunlock(r->l);
504 	_threadswitch();
505 	qlock(r->l);
506 }
507 
508 static int
509 threadrwakeup(Rendez *r, int all, ulong pc)
510 {
511 	int i;
512 	_Thread *t;
513 
514 	for(i=0;; i++){
515 		if(i==1 && !all)
516 			break;
517 		if((t = r->waiting.head) == nil)
518 			break;
519 		delthread(&r->waiting, t);
520 		_threadready(t);	
521 	}
522 	return i;
523 }
524 
525 /*
526  * startup
527  */
528 
529 static int threadargc;
530 static char **threadargv;
531 int mainstacksize;
532 
533 static void
534 threadmainstart(void *v)
535 {
536 	USED(v);
537 
538 	/*
539 	 * N.B. This call to proc() is a program's first call (indirectly) to a
540 	 * pthreads function while executing on a non-pthreads-allocated
541 	 * stack.  If the pthreads implementation is using the stack pointer
542 	 * to locate the per-thread data, then this call will blow up.
543 	 * This means the pthread implementation is not suitable for
544 	 * running under libthread.  Time to write your own.  Sorry.
545 	 */
546 	threadmainproc = proc();
547 	threadmain(threadargc, threadargv);
548 }
549 
550 int
551 main(int argc, char **argv)
552 {
553 	Proc *p;
554 
555 	argv0 = argv[0];
556 
557 	_threadsetupdaemonize();
558 
559 	threadargc = argc;
560 	threadargv = argv;
561 
562 	/*
563 	 * Install locking routines into C library.
564 	 */
565 	_lock = _threadlock;
566 	_unlock = _threadunlock;
567 	_qlock = threadqlock;
568 	_qunlock = threadqunlock;
569 	_rlock = threadrlock;
570 	_runlock = threadrunlock;
571 	_wlock = threadwlock;
572 	_wunlock = threadwunlock;
573 	_rsleep = threadrsleep;
574 	_rwakeup = threadrwakeup;
575 	_notejmpbuf = threadnotejmp;
576 
577 	_pthreadinit();
578 	p = procalloc();
579 	_threadsetproc(p);
580 	if(mainstacksize == 0)
581 		mainstacksize = 256*1024;
582 	_threadcreate(p, threadmainstart, nil, mainstacksize);
583 	procscheduler(p);
584 	_threaddaemonize();
585 	_threadpexit();
586 	return 0;
587 }
588 
589 /*
590  * hooray for linked lists
591  */
592 static void
593 addthread(_Threadlist *l, _Thread *t)
594 {
595 	if(l->tail){
596 		l->tail->next = t;
597 		t->prev = l->tail;
598 	}else{
599 		l->head = t;
600 		t->prev = nil;
601 	}
602 	l->tail = t;
603 	t->next = nil;
604 }
605 
606 static void
607 delthread(_Threadlist *l, _Thread *t)
608 {
609 	if(t->prev)
610 		t->prev->next = t->next;
611 	else
612 		l->head = t->next;
613 	if(t->next)
614 		t->next->prev = t->prev;
615 	else
616 		l->tail = t->prev;
617 }
618 
619 static void
620 addthreadinproc(Proc *p, _Thread *t)
621 {
622 	_Threadlist *l;
623 
624 	l = &p->allthreads;
625 	if(l->tail){
626 		l->tail->allnext = t;
627 		t->allprev = l->tail;
628 	}else{
629 		l->head = t;
630 		t->allprev = nil;
631 	}
632 	l->tail = t;
633 	t->allnext = nil;
634 }
635 
636 static void
637 delthreadinproc(Proc *p, _Thread *t)
638 {
639 	_Threadlist *l;
640 
641 	l = &p->allthreads;
642 	if(t->allprev)
643 		t->allprev->allnext = t->allnext;
644 	else
645 		l->head = t->allnext;
646 	if(t->allnext)
647 		t->allnext->allprev = t->allprev;
648 	else
649 		l->tail = t->allprev;
650 }
651 
652 Proc *_threadprocs;
653 Lock _threadprocslock;
654 static Proc *_threadprocstail;
655 
656 static void
657 addproc(Proc *p)
658 {
659 	lock(&_threadprocslock);
660 	if(_threadprocstail){
661 		_threadprocstail->next = p;
662 		p->prev = _threadprocstail;
663 	}else{
664 		_threadprocs = p;
665 		p->prev = nil;
666 	}
667 	_threadprocstail = p;
668 	p->next = nil;
669 	unlock(&_threadprocslock);
670 }
671 
672 static void
673 delproc(Proc *p)
674 {
675 	lock(&_threadprocslock);
676 	if(p->prev)
677 		p->prev->next = p->next;
678 	else
679 		_threadprocs = p->next;
680 	if(p->next)
681 		p->next->prev = p->prev;
682 	else
683 		_threadprocstail = p->prev;
684 	unlock(&_threadprocslock);
685 }
686 
687 /* 
688  * notify - for now just use the usual mechanisms
689  */
690 void
691 threadnotify(int (*f)(void*, char*), int in)
692 {
693 	atnotify(f, in);
694 }